TQM Doesn't Mean Total Testing

If you use nondestructive methods for testing package integrity, you may be able to accomplish a feat impossible with destructive testing�complete testing of your entire lot of packages. Your choice will, of course, depend upon your packaging style, volume, and process. But if you do find a method that accommodates your setup, you may just be able to give every package your seal of approval. Scrutinizing every package may give you and your customers piece of mind, especially when it comes to acute-care, high-value medical devices whose sterility is critical for both patient health and practitioner profitability.

There is some debate, however, on whether 100% package testing is the best way to ensure package integrity. In fact, medical packaging consultant Donald Barcan believes that its use could backfire. "I think the potential is there for companies to rely too heavily on 100% final package testing." For instance, if production line operators don't keep an eye out for any drift in sealing parameters like temperature or pressure, believing that any problems will be caught later on downstream, they may lose tight control of their processes.

Instead, Barcan argues that to prevent integrity breaches from reaching end-users, packaging professionals should "build quality into the process and not depend on final testing to catch process problems. Even 100% inspection does not always catch 100% of the problems." He advises audit testing, as long as your methods are appropriate for your packaging and can be validated.

Pat Nolan, vice president of the package testing firm DDL Inc., agrees. "The 100% inspection or testing of packages is not necessary if your processes are in control. Only sample testing is required to ensure your process is under control. In addition, statistically you do not gain much in confidence by doing 100% testing versus using a lot sampling plan like AQL [acceptable quality level]. We try to get our customers to perform process validation and then encourage them to set up total quality management programs to help keep their processes under control using sample testing and control charting. In the long run, this is much cheaper than performing lots of downstream testing."

Steve Franks of T.M. Electronics, however, argues that nondestructive testing can add to process control, not replace it. "If 100% nondestructive testing is available, then it adds to the process redundancy and overall reliability. All processes have failure modes, as far as I know, even testing processes. The process latitude can certainly be increased by intelligent design and selection of materials, and I think most competent packaging and process engineers strive for this."

Like Barcan and Nolan, though, Franks warns engineers not to rely on testing solely to ensure quality products. "My golden rule has always been, 'If you can't measure it, you can't control it.' You still need measuring tools to prove and improve your process."

Ultimately, you will discover what works best for your package and process. You may find that nondestructive testing, like some of the methods we explore on page 32, works best in concert with standard destructive audit tests like bubble-immersion and dye-penetration testing. Or, in the case of ultrasound and trace-gas sensing, which can often be several times more sensitive and repeatable than these destructive tests, you may want to rely on them instead, either for complete or audit testing. But do take the above advice�use testing to prove your process, not just your package. If you establish through testing that your process is control, chances are that your packaging is, too.

Daphne Allen, Editor